The invention relates to a rotating milling machine for use in processing rocky materials, especially concrete, asphalt, and masonry.
Machines of this type are used, among other things, for milling off walls, floors, or roadways, or for milling grooves into such structures.
An acceptable degree of progress in milling, particularly in harder materials such as concrete, can generally be achieved only via the use of very heavyweight machinery, having a high level of driving power and a high rate of advance, and producing a severe vibration of the machines and a high degree of abrasion of the milling chisels.
For this reason, attempts have long been made to provide these chisels with a percussion effect similar to that of a percussion drill or a jackhammer. In the patents DE 196 31 659 and DE 196 34 514 this was achieved for the first time. Here, in the case of the compressed air design of the former patent, the cost of producing the compressed air, and thereby the overall costs, are still relatively high, the force of impact, especially in the case of smaller dimensions, is limited, and a high level of power is required for generation of the compressed air, due to a low level of efficiency in the generation of compressed air and losses through leakage in the milling cylinder.
In the latter patent, the force of impact is very limited, and the cams are eroded relatively rapidly, or they become overheated due to friction losses. The percussion principle in this patent is more like that of a percussion drill than that of the more effective jack hammer.